For the training, rehabilitation and measurement of various physical parameters it is known to use apparatus of the home-trainer type which are constructed so as to receive various types of nonmotorized rolling vehicles. For example, these home trainers or turning assemblies may receive a bicycle or a wheelchair. Essentially, such apparatus comprise at least two motorized rollers interacting either with the wheel of the bicycle driven by the user by means of a pedalling action or with the two wheels of the wheelchair driven directly by the user's arms.
In point of fact, it has become apparent that the moment imparted by the user who therefore drives a rotary system, namely the wheel or wheels of the vehicle, is not constant. In the case of a bicycle, the moment passes from a maximum value to a value which is practically zero when passing through dead center. In the case of a wheelchair, the moment imparted is variable when the subject pulls and pushes with his arms. This moment is completely zero throughout the phase during which the user takes his hands off the driven wheels in order to reposition them with a view to exerting further effort.
Particularly in the case of a wheelchair, if the movable assembly exerts a constant braking moment, the use of such a chair becomes very difficult or even practically impossible: during each of the nondrive phases, i.e. when the user is no longer exerting any moment, the speed of the vehicle decelerates and may even become zero. The result of this is that, during each drive phase, the user has to exert an acceleration force preventing him from achieving a comfortable operating speed.
The state of the art may be illustrated by the teaching of Patent DE-A-2950605, which relates to a drive apparatus for a bicycle, whose function is to cause the resistance of the drive unit to vary by means of a complementary wheel.